[RFC PATCH v3 07/17] vsock: read from socket's error queue

[Arseniy Krasnov <AVKrasnov@sberdevices.ru>]

This adds handling of MSG_ERRQUEUE input flag in receive call. This flag
is used to read socket's error queue instead of data queue. Possible
scenario of error queue usage is receiving completions for transmission
with MSG_ZEROCOPY flag.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
 include/linux/socket.h   | 1 +
 net/vmw_vsock/af_vsock.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 13c3a237b9c9..19a6f39fa014 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -379,6 +379,7 @@ struct ucred {
 #define SOL_MPTCP	284
 #define SOL_MCTP	285
 #define SOL_SMC		286
+#define SOL_VSOCK	287
 
 /* IPX options */
 #define IPX_TYPE	1
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index eea2bcc685a2..b2da791d920b 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -110,6 +110,7 @@
 #include <linux/workqueue.h>
 #include <net/sock.h>
 #include <net/af_vsock.h>
+#include <linux/errqueue.h>
 
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
 static void vsock_sk_destruct(struct sock *sk);
@@ -2135,6 +2136,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 	int err;
 
 	sk = sock->sk;
+
+	if (unlikely(flags & MSG_ERRQUEUE))
+		return sock_recv_errqueue(sk, msg, len, SOL_VSOCK, 0);
+
 	vsk = vsock_sk(sk);
 	err = 0;
 
-- 
2.25.1